[asterisk-dev] proper way to signal user information layer 1 (ISDN)

[Tim Panton]

On 14 Sep 2007, at 14:24, Klaus Darilion wrote:

> Hi!
>
> In case of digital ISDN calls I want to signal the ISDN user  
> information
> layer 1 values between the dialplan (and maybe some apps) and the ISDN
> channel driver.
>
> I see two ways of doing this:
>
> 1. an ast_variable (a global one with _ prefix so that it gets copied
> automatically) which is read/written by the ISDN channel drivers  
> and the
> apps.
>
> 2. Adding ast_channel.userinformationlayer1. The channel driver and  
> apps
> can access the value directly and from dialplan this can be done by
> enhancing func_channel.c (http://bugs.digium.com/view.php?id=10217)
>
> This value exists only in ISDN, thus I'm not sure if a new member to
> ast_call is the proper way - but ISDN transfer capability is  
> similar and
> this is already added to ast_chan.

Is there any way we can make this work like the iax-variables ?
(see http://bugs.digium.com/view.php?id=7619)

If I understand the requirement right, this is similar, arbitrary  
name=value
pairs passed as part of the call setup. Data that isn't required to  
set the
call up, but useful for the recipient.

Clearly the name would have to change ;-)

Tim.